Aerial for wireless signaling.



c; s. FRANKLIN. AERIAL FOR WIRELESS SIGNALING.

APPLICATION II=ILED NOV. 27.1915.

1,296,177, Patented Mar. 4,1919.

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' l/VI/EN TOR cHARms-MMz a-mAA/Ku/v arm, or LONDON,

:. r or area, or new roan, at. a, a co ENGLAND, ASSIGNOR T0 5* .*0BATIOK0F FOR. WIRELESS SIGNALING.

Specification of Letters Patent.

at. a, ieia.

Patented application filed remember 27, 1915. Serial no. 83,714.

To all whom it may concern:

- Be it known that I, CHAnLEs SAMUEL FRANKLIN,.3. subject of the King ofGreat Britain, residing at Marconi House, Strand, London, England, haveinvented new and useful Improvements in Aerials for Wireless Signaling,of which the following is a specification.

The object of this invention is to provide a system of aerials forwireless signaling in which the radiation shall have a maximum value inone direction only, gradually diminishing in value to zero at 90 de oneither side of this maximum direction, and being ractically zerothroughout the other 180 It is well known that a frame such as arectangular circuit of wire which is placed in a vertical plane and inwhich high frequency alternating currents are induced, radiates electricwaves best in the two directions in the plane of the rectangle and notat all in the two directions at right angles to this plane. The polarcurve of radiationis in fact the well known figure of 8 consisting oftwo equal figures which are nearly circles. The waves at any two pointsequidistant from and one on each side of the rectangle and in its planeare at any instant of time equal and of opposite phase.

Let .us now suppose that two equal rectangular or frame circuits areerected in the same Vertical plane either so that they have one verticaledge common to both (in which case they may be considered as being inparallel) or so that they have one vertical edge of one rectangle adjaccnt to one vertical edge of the other, the two circuits beingconnected in series so that one is reversed as regards the other. Thenif high frequency alternating currents are induced in the two circuitsso that the currents traverse them in opposite directions, thecombination will as before radiate best in the two directions in theplane of the rectangles and not at all in the two directions at rightangles. The pdlar curve will again be a figure of 8 made up of twosimilar figures which are nearly circles. In this case, however, thewaves at any two points equidistant from and one on each side of therectangles and in their plane are at any instant of time equal and inphase with each other.

According to this invention there is employed such a doubleframe-circuit in the same or substantially, the same plane with a simpleframe circuit placed symmetrically with respect to the double circuit.The two circuits will have no mutual inductance or coupling edect on oneanother if they are properly proportioned; that is to say, alternatingcurrents existing in one will not affect alternating currents existingin the other. Under these conditions each circuit tends to produce itsown radiation independently of the other circuit.

This invention is illustrated by the accompanying diagrams, Figure 1showing the arrangement of two equal frames in parallel and Fig. 2 thearrangement of two frames in series.

In Fig. 1, GD, AdcD are two equal rectangular aerials having thevertical side A common. In AD is inserted a tuning ondenser K and. anoscillation generator I.

EFGH is a, simple rmtangular aerial having a tunin condenser L and anoscillation generator this aerial is erected in substantially the sameplane as the double rectangular aerial and symmetrically with respect toit, so that there is no coupling between the two s stems. I

The two osci ation generators Y and X produce oscillations of the samefrequency.

It is obvious that the phase of the currents in the two alternators maybe varied as desired by changing their relative positions on the commondriving shaft 2. However, any suitable or-known means may be used forproducing a desired-phase difference.

In Fig. 2 ABCD, abod are two equal frames connected in series as shown.

In one direction in the plane of the system of either arrangementprovided that the relative phase of the currents in the-two circuits iscorrect, the magnetic fields from the independent circuits are in phaseand produce a wave with an energy pro ortional to the square oftheir-sum; while direction the magnetic fields are of opposite phase andproduce a wave having an energy proportional to the square of theirdifierence.

Therefore the currents in the two independent circuits are so adjustedthat they produce waves of equal strength, the magnetic fields in onedirection in their plane will thus produce a wave with four times in theother two sets of oscillations should have a phase difierence of 90.

In the two directions at right angles to the plane of the circuitsneither produces any waves.

The result is-therefdre that practically all t e'energy is radiated onlyon one side of the planethrough the system atv right angles to itsplane. On that side the polar curves of the two frames add; on the otherside of the line the two curves practically neutralize each other.

In practice it is necessary to introduce condensers into the circuitswhich need not necessarily be rectangles, so as to tune them to thefrequency emplov ed.

To obtain the best hrectional effects the circuits should be entirelyinsulated from the earthbut good directional efi'ects may be obtained ifthe earth be used as part of one or both circuits. 7

Such a system of circuits may also be used for receiving, as will beobvious to those skilled in the art from a study of the foregoindescription.

at I claim 'is: y

1. The combination with a directive double looped aerial of a directivesingle looped aerial erected substantially in the plane thereof andsymmetrically therewith.

2: The combination with a directive double looped aerial of a directivesingle plane thereof and symmetrically therewith,

and means for producing in the two aerials waves of equal stren h.

3. The combinatlon 'with a directive double looped aerial of a"directive single looped aerial erected substantially in the planethereof and symmetrically therewith, and means for producing in the twoaerials waves of e ual strength but with a phase difference 0% 90.

4. The combination with a double looped aerial of a single looped aerialpositioned substantially in the plane of said double looped aerial andsymmetrical therewith, and means for producing in the two said aerialswaves of substantially the same length. 7

5. The combination with a double looped aerial, of a single loopedaerial positioned substantially in the plane ,of said double loopedaerial and symmetrical therewith, and means for producing. in thetwosaid aerials waves of substantially the 'same length but of differentphase.

6. The combination with a double looped aerial, of a sin le loopedaerial erected substantially in tie plane thereof and symmetricallytherewith, and means for producing in the two aerials waves of equallength but with a phase difi'erence of 90.

7 A radio signaling system comprising in combination a double loopedaerial and a single looped aerial in profimity thereto, the said two,aerials being parallel and arranged so that they have no mutualinductance.

CHARLES SAMUEL FRANKLIN.

